At the present time, one of the most rapidly expanding technologies in data processing is that of electronic document distribution to produce an automated office environment. This technology utilizes communication networks in an office-information-interchange system or electronic mail. Such a network is a complex interconnection of processing terminals or work stations of varying capabilities performing an assortment of data processing and text processing operations with respect to document production and distribution. A major problem that such networks present is the variety of interfaces and data forms which must be accommodated to functionally interconnect the various participating work stations and processors into an operational information-interchange system. In a conventional document distribution, not only must the various processing terminals be functionally interconnected but the system must provide the basic capability to enter and edit information, distribute information and print or display information. Irrespective of the network configuration, the system must be easy to use if it is to be effective. Also, the complexities of the various interface and data forms must be transparent to the users. In other words, the system must handle and distribute the documents with a minimum of operator intervention. To expect the sender of information to know very much about processor and data form requirements is unrealistic. The sender should be able to request that information be distributed. He should not have to be concerned about the expedients used in such a distribution.
To this end, the art has been developing uniform data streams which are discernible by the various processor-work stations participating in the document distribution network. Architectures have been defined which specify data stream content as well as the rules involved in the communication in the network. These data stream architectures specify the form of the information by describing the syntax and meaning of allowable elements in the data stream. Reference is made to the article entitled "Electronic Information Interchange in an Office Environment" by M. R. DeSousa, IBM Systems Journal, Vol. 20, No. 1, 1981, at page 4. This article describes a typical document distribution or interchange architecture which permits information to be carried from a sender to a recipient in such a network without requiring that both be interactively communicating during the distribution process. Further, it permits a sender to send information such as a document to multiple recipients with a single distribution request. Finally, the distribution architecture provides for services such as security base storage during distribution and confirmation of delivery.
In data distribution networks, a uniform data stream may be considered to comprise two major components: the above described document interchange architecture which relates to communication and processing of the document and the document content architecture which is representative of the content and format of a particular document.
The document interchange architecture involved in the distribution and processing of documents in distribution networks is described in even greater detail in the article entitled "The Document Interchange Architecture: Member of a Family of Architectures in the SNA Environment", by T. Schick et al, IBM Systems Journal, Vol. 21, No. 2, 1982, at page 220. Because of the wide variety of data processing equipment available in the current office environment together with the need to make document distribution network readily compatible with equipment which may be made available in the future, document distribution networks must have the capability of integrating into the system communicating processors of varying levels of data processing capabilities. Existing document distribution systems such as those described in the above mentioned articles provide for a uniform data stream whereby data processing stations or work stations with varying data processing capability may communicate with each other by following the protocol of the document interchange architecture. In my co-pending application entitled "An Electronic Document Distribution Network with Uniform Data Stream", Ser. No. 06/440,484 filed on the same day as the present application, now U.S. Pat. No. 4,532,588, I provided for a document interchange architecture and network for communications between and processing of data by terminals of varying data processing capabilities. The communication is handled through a uniform data stream which remained unaffected by the data processing capabilities of any of the communicating data processors involved in the processing.
The system of this co-pending application is of course based on the premise that a given pair of communicating processors want to communicate with each other in document exchange and processing, i.e., that the processor having the greater data processing capabilities wants to communicate with the processor having the lesser capabilities. In a document distribution network, this may often not be the case. For example, let us assume that a communicating processor work station in Dallas, Tex. wishes to communicate with another communicating processor in Macon, Ga. In order for the work station in Macon to be able to completely handle the document communication and processing requirements with respect to the document which the Dallas processor wishes to communicate, the work station in Macon must have distribution, application processing and document library services capability. However, in extensive document distribution networks, communicating processor work stations are being continuously and dynamically added to the system, removed from the system as well as having their respective processing capabilities continually changed, either upgraded or downgraded. For instance, on a given day the communicating data processor work stations at a given location may have only document library services capability but two or three days later capabilities of the particular work station are enhanced so that it now includes distribution services capabilites. In another instance, a given communicating processor work station may provide library services only during certain time periods because these library services may be available to the processor on only a time shared basis. As a result, in such a dynamically variable document distribution system or network, the most that a given communicating processor work station is likely to know or have available with respect to the capabilities of any other work station is that communicating processor work station exist at a given location.
Thus, there appears to be a need in document interchange networks having data processing work stations or terminal with dynamically variable capability for expedients whereby any linked processors may determine their respective variable processing capabilities and determine whether the document interchange between these two terminals is feasible based upon these variable capabilities; the present invention is directed to this need.